Control means for web slitting and the like



April 13, 1954 D. A. THEOBALD CONTROL MEANS FOR WEB SLITTING AND THE LIKE 5 Sheets-Sheet l Filed Dec. 2", 1950 "pril 13; y'1954 yla. A. THEOBALD CONTROL MEANS FOR WEB SLITTING AND THE LIKE 5 Sheets-Sheet 2 Filed Dec. 2, 1950 April 13, 1954 D, A. THr-:oBALD CONTROL MEANS FOR WEB SLITTING AND THE LIKE Filed Dec. 2", 1950 5 Sheets-Sheet 3 April 13, 1954 D. A. THEOBALD v 2,675,437

CONTROL MEANS FOR WEB SLITTING AND THE LIKE Filed Dec. 22, 1950 5 Sheets-Sheet 4 April 13, 1954 D. A. THEOBALD 2,675,437

CONTROL MEANS FOR WEB SLITTING AND THE LIKE Filed Dec. 22, 1950 5 Sheets-Sheet 5 Patented Apr. 13, 1954 CONTROL MEANS FOR WEB SLITTING AND THE LIKE Delbert A. Theobald, Cincinnati, Ohio, assigner to Container Corporation of America, Chicago, Ill., a corporation of Delaware Application Dember 2,2, 19,50, Serial No. 202,201

7 Claims. (Cl. i300-61.18)

The present invention relates to the maintenance of a predetermined lateral or transverse relation between a traveling web and means f or 4ac :ting on the web, and more particularly to mechanism for eiecting movement o such means automatically in correspondence to lateral shift* ing cr creeping of the web, so as to maintain the lweb and means in substantially fixed relation transversely of the direction of travel ci the web.

In the disclosed embodiment of the invention, control mechanism is Aincorporated in a machine for slitting and creasing a traveling web of relatively stiff paperboard, such as corrugated. vor solid breboard, moving from a suitable co1nbining machine. The slittingand creasing machine7 commonly called a slitter, comprises a pair of rolls between which the web passes, the rollsccnsisting oi shafts carrying circular knives and .creasing elements for cutting and creasing the web in parallel lines along the direction of travel of the web. The rolls, or the slitter itself, may be shifted transversely of the web direction by suitable mechanism including a reversible elec.u tric motor. Manually operable switch means are provided for effecting initial adjustment oi the slitter means in a predetermined relation to the web, and switch means automatically operable by `an edge of the web are provided for shifting ythe slitter means in the same direction and degreeas the web, in the event of creeping of the web laterally in either direction, so that .the predetermined relation is automatically maintained. The weboperable switch means comprise a switch unit arranged to shift with the shiftable slitter means and disposed adjacent an edge .of the web. The switch .unit includes a movable member adapted to be engaged by the web edge, and a pair of switch elements biased one toward closed position and the other toward open 4position in the direction of the movable .member .and engageable thereby. While the web and slitter means remain in the vdesired. relation, the movable member is held so positioned that both ,switch elements are open, but upon creeping of the web in one direction or the other, one or the k other of the switch elements is closed to actuate the ,movtor for shifting vthe slitter means ,correspondingly until the web creepage ceases and the desired relation is reestablished. To avoid possibledamage to the slitter, limit switches are provided to :shut o ii the motor when the lslitter means reach `a predetermined point in one directionor the other, these switches lbeing operated by 1the slitter means.

One important advantage oi the present invention is a saving .of web material. In ordinary siitter operation, the desired trimming of the web to provide clean, smooth edges necessitates the removal of relatively wide strips from both edges of the web, since each edge trimming knife must be disposed inwardly of the adjacent Web edgea distance at least equal to the observed mai;- imum extent of web Creepage. Otherwise, an u ntrimmed portion of an edge may pass the edge knife inwardly thereof. AIn such case, the edge would not be trimmed at all, and furthermore the web at this portion would be of less than the desired trimmed width. By the use of the invention, the edge trimming knives need be set inwardly of the .web edges only a slight distance, just suiiicient to vassure that irregularities of .the edges will not extend inwardly of the knives. Thus a maximum of usable web material is obtained. kand the trimmed edge strops, which are scrap, are held to a minimum. Another advantage of the invention is that it `operates from va single edge of the web, so that access to both edges Aof the web, sometimes entailng danger, is not necessary, and no need exists for coordinating separate means at opposite yedges of the web. A further advantage is that vthe movable member has a relatively long lineof Contact with the web edge, so as to bridge short breaks or indentations in the edge and avoid unnecessary Ishifting of the sltter means. The invention is not limited in application to a slitter, since the principlesemployed readily permit. of its incorporation in other apparatus for acting on a traveiing web.

An object of the invention is to provide control mechanism vfor maintaining in predetermined transverse relation a traveling web and means for acting linearly on the web along its direction of travel. Another object is the 2provision of mechanism responsive ,to `lateral creeping of a traveling web yto effect corresponding shifting of `means for acting on the web. A further object is the provision of vcontrol mechanism for maintaining in a predetermined aligned relation a .traveling .web and means for acting on the web along its direction of travel, which mechanism is voperable by oneedge of the web. It L,is also 1an object to `provide control mechanism for 4maintaining a substantially fixed relationship between fa utraveling web subject to creeping laterally in either direction and means for `ac ting Vontl'le web shiftablein either direction .transversely .of ,the web.

Other .and further objects, advantages. and

features of the invention will be apparent to those skilled in' the art from the following de scription and the accompanying drawings, in which:

Fig. 1 is a side elevational view of apparatus incorporating the present invention;

Fig. 2 is an enlarged vertical sectional view taken as indicated by the line 2--2 of Fig. 1;

Fig. 3 is a fragmentary plan view of the apparatus of Fig. 1;

Fig. 4 is an enlarged vertical section taken as indicated by the line 4-4 of Fig. 2;

Fig. 5 is an enlarged fragmentary sectional view of a portion of the apparatus as shown in Fig. 2;

Fig. 6 is an enlarged vertical section taken as indicated by the line 6 6 of Fig. 1;

'Fig 7 is an enlarged vertical section taken as indicated by the line 1-1 of Fig. 2;

Fig. 8 is an enlarged detail view of a portion of Fig. 3;

Fig. 9 is a vertical sectional view taken as indicated by the line 9-9 of Fig. 8; and

Fig. 10 is a partly diagrammatic representation of the electric circuit arrangement of the invention.

Referring to the drawings, there is shown in Fig. 1 a pair of end rolls 20 of a conventional machine for combining a plurality of paperboard Webs into a single web W which is carried between the rolls by suitable belts 2|. The rolls 20 are rotated by any suitable means, and mounted on the same shaft as one of the rolls is a gear 22 meshing with a pinion 23 on a common shaft with a sprocket wheel 24, so that the latter is kdriven by the roll driving means.

Spaced forwardly of the rolls is a machine for slitting andv creasing the web W, commonly ycalled a slitter', which is designated generally by the reference numeral 25. The slitter 25 comprises a suitable frame extending across the direction of travel of the web and including end standards 26 and 21 in which is journaled a main shaft 2B, the standard 28 being disposed on the same side of the web as the sprocket 24. Mounted on the shaft 28 between the standards 26 and 21 and in spaced relation to one another, are two` Y- shaped roll supports 29 (only one shown), each of which has three branches or arms 3U extending radially of the shaft 28. The arms 39 of the supports 29 are arranged in registering pairs, and between each registered pair of arms there extends a pair of horizontal-axis, cooperable slitfting and creasing rolls 3| and 32 suitably journaled in the supports 29.` Each roll 3| is disposed a greater distance radially outwardly of the main shaft 28 than its cooperative roll 32. Each roll 'comprises a shaft and suitable creasing elements (not shown) and knife elements such as the circular knives 33. Such elements may be fixed on 'the shaft at axially spaced points, according to .the desired spacing of the lines along which the web is to be creased and cut. These elements are formed as well known in the art so that they may be adjustably positioned on the shafts.

As best shown in Fig. 1, the roll supports 29 may be rotated about the axis of shaft 28 to dispose Vany one pair of rolls 3| and 32 above the'main shaft 28 in operative position to act on the web W as it travels between them from the rolls 20 of the combining machine. The other two pairs of rolls are thus positioned below the web, so that while the web is passing between the operative rolls these other rolls may be prepared for later operation on a web. Rotatably mounted on a shaft carried by the end standard 2B is a sprocket wheel 34 driven from the wheel 24 by a sprocket chain 35. On the same shaft as the sprocket 34 is a gear 35. Each of the arms 30 of the adjacent roll support 29 has mounted thereon a gear 31 meshing with a gear 38 on the end of the shaft of roll 3|, which in turn engages with a gear 39 on the shaft of the other roll 32. The gear 31 of each arm 30 is arranged to mesh with the gear 36 as the arm is rotated to the vertical position, so that the rolls 3| and 32 may be driven together with the combining machine and by the same means. Rotation of the roll supports 29 of course is effected by turning the main shaft 28, which is done by means of a large gear 40 on the shaft. The gear 40 is driven when desired by any suitable means (not shown).

Means are provided to permit shifting of the slitting and creasing rolls 3| and 32 axially, or in other words transversely of the web, in either direction. For convenience in description, the side of the slitter 25 at which the standard 25 is located may be considered as the inner side, and that adjacent the standard 21 as the outer side. Statements as to inward or outward movement are made with reference to such arbitrary designation of the sides. As best shown in Fig. 6, the shaft 28 projects outwardly through the gear 40 and through a forward portion 4| of the standard 21 which has a split bearing 42 for the shaft. The shaft has an axial recess 43 extending from its outer end, and a diametral slot 44 extends through the shaft, providing radial openings into the recess 43. The gear 40 has secured on the outer side of its hub portion a pair of radially disposed bars 45 which extend with a sliding fit into the shaft 28 through the opposite endsor openings of the slot 44, but do not project into the recess 43.

On the inner side of the gear hub portion is a plate 46 with an axially extending annular ange 41 having a radial lip 48. The flange and lip are received in a correspondingly formed groove 49 in the parts of the split bearing 42 in the standard 4| to hold the gear 40 against axial movement while allowing rotation thereof. The groove 49 may be provided in any suitable manner, as for example by providing a flange and lip on the split bearing members to interlock with the lipped flange 41 as shown. It will be apparent that by this construction the main shaft 28 is locked to the gear 49 by the bars 45 so as to rotate whenever the gear is turned, but may slide or shift axially relative to the gear. In the recess 43 is disposed a nut member 50 which has a pair of radial projections 5| extending through the openings provided by the slot 44 and engaged in a suitable annular recess 52 in the standard 21. Extending into the recess 43 and working in the nut member 50 is a worm shaft 53 threaded at its inner end and having a gear 54 keyed or otherwise secured on its outer end. A sprocket wheel 55 is also secured on the outer end of the shaft 53. and may be formed integrally with the gear 54 as shown. The shaft 53 passes through a suitable plate 56 on the end of the main shaft 28 closing the outer end of the recess 43, and through a'rotatable thrust block 51 fitting closely Within the recess. The block 51 is secured to the shaft 53 by any suitable means, such as a pin 58, and serves to hold the shaft 53 against axially outward movement relative to the main shaft 28, while the hub of the gear 54 or sprocket 55 prevents rela-` tive inward movement. Suitable thrust bearings 59 are provided on each side of the' closure plate 56. Rotation of the gear 54 in one direction or the other results y"in -axial 'movement one wayor the other of the main yshaft 28 relative 'to the standard 21 by reason -of the threaded engagement of the worm shaft 53 in lthe nut vmember `5|), and such movement of the shaft 28 is of course shared by the supports 29 and their arms 3'0 and rolls 3| and'SZ, aswell asthe gear-54 and sprocket wheel 55.

As best shown Figs. 1 and 2, the Agear 54 is driven by a reversible electric motor 60 through a sprocket wheel '6| mounted on a slip clutch-B2 on the 'motorfshaftand another sprocket wheel 63 on a shaft 64 journaled in suitable Ibearings 65 lon a support adjacent the gear- 54. A sprocket chain 66, for which an idler sprocket wheel "61 may be provided, is trained around the sprockets 51| vand 63. A gear -36'8 is secured on-the shaft l64 meshing with the gear 54. Theaxial `extent of the gear v68 is substantially equal to thedistance through which the main shaft 25 maybe shifted, so that the gears will remain in mesh when the gear 54 moves axially with the shaft 28. When the motor 60 is operated, the gear 68 rotates to drive the gear 54 and shift the shaft 28 and the parts carried thereby in one direction or the other, depending on the direction of rotation of the motor. The motor is controlled by a circuit yarrangement including manually operable switches for initial positioning of the slitter means in desired relation to the web W and automatically operable switch means for shifting the slitter means in'accordance with creeping of the web, so as to maintain lche desired relation. This arrangement is showin in `Fig. l0, and is hereinafter described in connection therewith. The term slitter ymeans is Aused to indicate generally the main shaft 280i the slitter 25 and the parts carried thereby for shifting therewith.

'Referring new particularly to Figs. 2, 3, and 5, there is provided at the rear of the slitter 25 a horizontal supporting bar extending transversely and supported from the standards 26 and H21 slightly below the plane of the web W .by suitable brackets 1|, only one of which is shown. The end of the bar 10 adjacent the standard 21 lprojects outwardly beyond the plane of the sprocket wheel 55, and has its upper portion cut away to provide room for a sprocket wheel 12, in the plane of the sprocket 55, supported on the outer end of a shaft 13 slidably journaled in a bearing block 14 mounted on the bar 10. The inner end yportion of the shaft 13 is enlarged-and threaded to work in an internally threaded block 15 secured on the bar 10. The inner end of the shaft 13 extends into a recessed block 16 bolted or otherwise secured on a flat -bar 11 slidable on the upper face of the supporting bar 10. The inner end of the shaft 13 is reduced to form a shoulder and has a disk 18 bolted thereon to provide with the shoulder a groove receiving the radially inner portion of -a suitable annular bearing member 19. The radiallyouter portion of the bearing is engaged in a groove provided in the recessed block 16 in any suitable manner, as by the annular radially hanged-insert 80 secured to the block 16 and slide bar 11 by screws or the like. The sprocket wheel 12 is driven from the sprocket wheel 55 by means ofa chain 8|, so that the slide bar 11 may be shifted in one direction or the other along the supporting bar 10, depending upon the direction of rotation of the sprocket 12, by lmeans of the shaft 13. The shaft 13 is-threaded to correspond to the worm shaft 53,;so that shifting of @the slide bar 11 cor-responds to ythat of the main shaft'n. An idler wheel 82 engaging with the sprocket chain `8| may be provided adjacent the Wheel 12, on a shaft 83 mounted in a bifurcated member 84 pivoted by bolts 85 or the like on the -ends of a block 86 depending .from the supporting `bar 10. An adjusting screw 81 extends through the yoke element 88 of the member 84 to engage against the underside of the depending block 86 for varying :the position ofthe sprocket 12.

vA plurality of vslotsil are formed in the slide bar 11, spaced longitudinally therein. Through each slot there vextends a stud bolt 9| secured in Ithe supporting bar 100 and having thereon a roller Y92 of Ia diameterslightlyless than the width of the-slot and of less thickness than the bar 11. A disk or washer 93 is disposed on bolt 9| bridging the slot and secured by the head of the bolt. This arrangement keeps the slide bar in properly aligned relation while permitting it to slide back and forth on the supporting bar. The length of the slots 90 corresponds to the distance the slitter means and slide bar 11 may be shifted.

An electric switch unit generally vdesignated 94 is adjustably mounted on the slide bar 11 for automatic control of the reversible motor 69 'in accordance-with lateral movement of the web'W. This is best shown in Figs. 3 and 9. Secured on -the upper surface of the slide bar 11 is a tenori strip 95 dovetail'ing with a mortised block 86. A bracket plate 51 extending rearwardly of the supporting bar 1i! is bolted or otherwise secured at its forward end on the mortised block 98, so that it may be moved therewith on the slide bar 11 along the tenen strip 95 to a desired position. The plate 51 is locked at any point along the tenon strip by means of a clamping bolt 98 or the like extending through the block 55 with its end bearing on the tenori strip.

'The plate 91 is disposed substantially `at `the level of the web W. A generally L-shaped web guide T99 is provided having one arm secured on the forward end of the plate 91 and extending inwardly therefrom, the other arm extending rearwardly and upwardly from .the ilrst arm and being adapted to overlie the -outer Yedge of the web W. In its rearward portion the plate 01 has an aperture extending vertically therethrough counterbored at each end to provide seats for bearings |00 in which is journaled a pivot having a block |02 on its upper end and a colla-r |03 on its lower end. A relatively broad blade member or palm |04 is secured to the pivot block |02 with the broad surface of the blade in substantially perpendicular relation to the upper and lower surfaces of the plate 01 and to the upper and lower surfaces of the traveling web W. The palm |05 swings readily on its pivot, and is curved so as to extend forwardly from the pivot and inwardlyof the plate 91. The inner edge of the plate is recessed to receive suitably cased switch elements |05 and |55 having projecting plungers |01 and |08, respectively, urged toward the palm |04, the switch element |05 thus'being biased toward closed position and the switch element |06 toward open position. The switch element |05 is disposed nearer the rear end `of the plate 91 than the vswitch |05. These switches are suitably connected to the motor 60 by conductors (not shown) in conduits |00, at least a portion of each of which is iexible. The circuit arrangement is illustrate-d in Fig. 10.

The palm E04 is so Vcurved that when it bears on the outer edge of the web W with the web in a predetermined relation to the slitter means,

it engages the plunger |01 of the switch |05 and holds it in open position, but does not close the switch |06. This relative position is shown in Fig. 8 in full lines. If the web W shifts laterally or creeps away from the switch unit 94, the plunger |01 is allowed to move so that the switch |05 is closed and causes the motor 60 to drive the slitter means and the switch unit 94 inwardly, or in other words in the direction of web creepage. The plunger |01 urges the palm |04 against or toward the web edge until creepingstops, when the palm is caused by the web edge to swing relative to the plate 91 and again causes the switch |05 to open, the web and slitter means then again being in the predetermined relation. If the web W creeps toward the switch unit 94, it moves the palm |04 against the plunger |08 to close the switch |06, causing the motor 60 to drive the slitter means and switch unit in this opposite direction of web creepage until the creeping stops. The movement of the slitter means and switch unit is stopped immediately thereafter, as the plate 91 with the switches |05 and |06 moves outwardly relative to the palm |04 to permit the plunger |08 to return to its normal position and open the switch |06. In Fig. 8, an outwardly shifted position of the switch unit 94 is indicated in broken lines. The switch elements and palm are so adjusted and arranged that a certain amount of play is permitted without closingof either switch, to allow for minor lateral movements of the web and slight irregularities in the web edge. Because the palm and web edge normally contact each other for a considerable distance', narrow breaks or indentations in the web edge do not cause useless shifting of the slitter means, for the web edge at one end or the other of the gap holds the palm in normal position.

As a precaution against the possibility of the slitter means being shifted so far in either direction as to cause damage to the slitter or motor, two limit switches and are provided for opening the circuits between the switch elements |05 and |06, respectively, and the motor 60 at ,1

predetermined limits of movement of the slitter means. The limit switches are supported from the supporting bar below the slide bar 11 by brackets ||2 and ||3, as best shown in Figs. 2, 3, and '7, the Switch ||0 being disposed in a plane forwardly of the switch Each switch has a plunger ||4 projecting vert'cally from the top of its casing and carrying a suitable roller H5. The plungers ||4 are biased upwardly to hold the switches normally closed, and are spaced apart a distance approximating the extent of axial movement allowed the shaft 28. A pair of cam members ||6 and ||1 are secured on the edge of the slide bar in the planes of the rollers ||5 of the switches 0 and respectively, and depend below the tops of the rollers. The cam members are in the form of plates having angled lower edges adapted to er1- gage the rollers and depress the plungers when they pass over the switches. The cam members ||6 and ||1 have horizontal slots ||8 adjacent their upper edges through which securing bolts ||9 extend into the slide bar 11, the slots permitting limited adjustment of the cam members alongI the slide bar for varying the extent of movement allowed the slitter means. As the slitter means and slide bar 11 move inwardly or outwardly in accordance with lateral web movement, the slide bar carries the cam member ||6 or ||1 toward engagement with the roller coil |20.

providing a circuit through coil |2|.

4| I5 on the plunger ||4 of the switch ||0 or respectively. If the movement continues to the predetermined limit, the cam member ||6 depresses the plunger of the switch I0, or the cam member ||1 depresses the plunger of the switch as the case may be, thus opening the switch and stopping the motor. Further shifting of the slitter means and slide bar is thus prevented. even though the web W continues to creep and one of the switch elements |05 and |06 is closed.

In Fig. 10, a circuit arrangement for controlling the motor 60 by either manual or web-actuated switch means is shown diagrammatically. One side of the motor is connected to coils and |2| of a suitable A. C. reversing starter.

Actuation of the motor through coil |20 causes rotation of the motor shaft in a direction to shift the slitter means and slide bar 11 inwardly, while motor actuation through coil |2| results in rotation in the opposite direction to cause outward shifting of the slitter means and slide bar. The other side of the motor 60 is connected to a switch arm |22 movable between a contact |23 to provide for manual control of the motor and a contact |24 for automatic control of the motor by the web W. The switch arm |22 may also have an off or disconnected position between these two contacts. The contact |23 is in a manually controllable circuit having two branches |25 and |26, the branch |25 being connected through limit switch ||0 to the coil |20 and the branch |26 through limit switch to coil |2|. Each branch has two gaps therein defined by pairs of spaced contacts. vBranch |25 has pairs of contacts |21 and |29 therein, and branch |26 has contact pairs |29 and |30. Push button switches |3| and |32 are disposed in the circuit, the switch being biased to a normal position bridging the contacts |29 in the branch |26 and being movable to close the pair of contacts |21 in the branch |25, while the switch |32 is normally biased to close the pair of contacts |28 in the branch |25 and is movable to bridge the contact pair |30 in the branch |26. Thus when the switch arm |22 is connected with the contact |23, the motor may be actuated to shift the slitter means inwardly by pressing of the push button switch |3| to close the pair of contacts |21, the switches |3| and |32 then completing the branch |25 to provide a circuit through the The motor may be operated to shift the slitter means outwardly by movement of the switch |32 to close the pair of contacts |28 and with the switch |3| complete the branch |26, The limit switches I |0 and are operable as already explained to prevent excessive shifting of the slitter means when the motor is operated by the manual switches.

For automatic actuation of the motor by the outer edge of the web W, the contact |24 is connected to one contact of each of the switch elements |05 and |06. The second contact of switch |05 is connected through the limit switch ||0 to the coil |20, while the second contact of the switch |06 is connected through limit switch to coil |2|. When the switch arm |22 is con-4 nected with the contact |24, closing of the switch |05 completes a circuit through coil |20 to cause the motor to shift the slitter means inwardly, while closing of switch |06 completes a circuit through the coil |2| for operation of the motor to shift the slitter means outwardly. The closing of switch elements |05 and |06 as a result of web creepage inwardly or outwardly has been 9 explained above. When both switch elements and |06 are open, as in the normal or predetermined position illustrated.. in Figs. 8 and 10, the motor of course does not operate.

To support the web W as it passes from the rolls 20 of the combining machine toy the slitter 25, a table i33 may extend rearwardly of the slitter. The table may be supported in any suitable manner, as for example by brace members |34 and |35 extending from the frames of the slitter and of the combining machine.

While the operation of the disclosed embodiment of the invention has been` explained in connection with the description of the construction, it may be reviewed brieily. With the web W in position to pass between the slitting and creasing rolls 3|, the desired relation between the web and slitter means is obtainedl by adjusting the switch unit 94 along'the slide bar 'Vl and moving the slitter means to the desired position by manipulation of switches |3| and |32. The web W may travel through the slitter 25 during this adjustment, if desired. The switch arm |22 is then moved to circuit-closing. relation with the contact |24 to render the switch elements |05 and |06 effective to control the motor 60, the slitter means being substantially in the desired relation to the web W', with the palm |04 engaging the web edge substantially as in Figs. 8 and l0. As the web passesy through the slitter 25,

lthe palm |04 remains in the relation shown so long as thek web W moves directly along its line of travel.. Upon lateral creeping of the web in either direction, the palmi. |04 swings in the same direction to cause closing of one or the other of the switch elements |05 and |06 as fully explained above and thus eiiect shifting oi the slitter means in the same direction and degree as the web, by means. of the reversible motor 80. The web W and slitter means are thus automatically maintained in the predetermined lateral or transverse relationship tov which they were set by the initial adjustment.

It will be seen that the presenty invention effectively maintains a predetermined aligned relation between a traveling web and means for acting on the web, by causing such means to shift transversely of the web direction of travel in accordance with lateral creeping of the web. Furthermore, the. invention provides for control of such shifting by an edge of the web, so that adjustment need be made relative to only one web edge with resultant simplication of adjustment and control due to elimination of any necessity to adjust and coordinate control means at opposite edges of the web. Trimming of the web edges requires removal of a minimum of material, since no allowance need` bev made for lateral shifting of the web relative tothe trimming means. The invention is vreadily embodied in means which are lsimpleto provide andy apply,

and which do. not readily break or become dis'- ordered. Although the invention has been disclosed as employed in connection with a web of paperboard, it is not limited to such use, nor is it limited to maintainingk a web in av desired relation to slitting and creasing means, for it is readily applicable and adaptable to operation with webs of other material than` paperboard and to control of other means for acting on a web.

Since many changes may be made in the disclosed embodiment of the invention without departure from the inventive. concept, it is not intended that the invention be. limited otherwise than as required by the scopeV ofthe appended .1,0 claims, due regard being given to the spiritV as well as the literal wording thereof.

I claim:

l. For use in a mechanism for maintaining a predetermined aligned relationship between a traveling web and transversely shiftable means for acting on the web wherein there are electrically' actuatable operating meansy forr shifting the rst. said means transversely of the web; means for controlling the operating means in predetermined relation to any lateral creeping of the web with respect to the direction of travel of the web, said control means comprising an electric switch unit adapted to be mounted in fixed relation to the shiftable means and shiftable therewith, said switch unit having a relatively movable blade member adapted to bear on an edge of the web, said switch unit includl.. th.)

ing a pair of parallel switch elements biased in the direction of said movable blade member and engageable thereby, one of said switch elements being biased towards closed position and the other of said switch elements being biased toward open position, said one switch element normally engaging the movable blade member at all times to urge such member against the web edge and being held open thereby in said predetermined relation of the web and shiftable means, said oney element being closed upon creeping of the web away from the switch unit thereby to actuate said operating means to move the shiftable means in thev direction of web creepage, and said other switch element being closed by movement oi the movable member upon creeping of the web toward the switch unit thereby to actuate said operating means to eicct movement of the shitable means in the last said direction of web creepage, the pair of biased switch elements being arranged in parallel spaced relation to each other and adjacent one edge of the traveling web, the movable member of said switch unit comprising an elongated blade-shaped web edge follower interposed between the pai-r of biased switch elements and the edge of the travel-ing web and having one face extending a substantial distance along and normally in contact with said edge.

2. For use in an apparatus for performing an operation on a traveling web subject; to lateral creeping wherein there are transversely shiftable means for acting on the web in predetermined relation to the web edge, electrically actuatable operating means for shifting the said shiftable means in either direction transversely of the web; means for controlling said operating means to accord with creeping ofthe web, comprising an electrical switch unit adapted to be mounted in fixed relation to the shiftable means and shiftable therewith and disposed adjacent to an edge of the web, said switch unit, including a movable follower member normally engaging in abutting relation against the adjacent web edge, and having rst and second parallel switch elements reto effect actuation of the operating means to move said shiftable means in said direction of web creepage, the second switch element normally remaining open and being closed by the movable member upon creeping of the web toward the switch unit thereby to actuate the operating means to effect movement of the shiftable means in the last mentioned direction of web creepage, the pair of biased switch elements being arranged in parallel spaced relation to each other and adjacent one edge of the traveling web, the movable member of said switch unit comprising a curved elongated blade-shaped web edge follower interposed between the pair of biased switch elements and the edge of the traveling web and having one face extending a substantial distance along and normally in contact with said edge.

3. For use in a mechanism for accurately trimming a traveling web to a predetermined desired width, wherein there are web advancing means, web shearing means mounted for shifting movement transversely of the web, electrically actuatable operating means including a reversible electric motor for shifting said shearing means in either direction transversely of the web and means for controlling the operating means in accordance with lateral shifting of the web, said controlling means including a reversing -circuit for said motor and an electric switch unit in said circuit; said switch unit being adapted to be mounted in relatively fixed relation to the shearing means and having first and second parallel switch elements each operable to close independently of the other to effect actuation of the motor to shift the shearing means in one direction or the other, said switch unit also including a movable follower member normally bearing on an edge of the web and responsive to lateral shifting of the web in one direction or the other to effect closing of one or the other of said switch elements thereby to operate said motor in one direction or the other to move said shearing means in the same direction as that in which the web may shift, one of said switch elements normally urging said movable follower member against said web edge at all times, the pair of biased switch elements being arranged in parallel spaced relation to each other and adjacent one edge of the traveling web, the follower member of said switch unit comprising an elongated blade interposed between the pair of biased switch elements and the edge of the traveling web and having one face extending a substantial distance along and normally in contact with said edge. i

4. For use in a mechanism for accurately trimming a traveling web to a desired width wherein there are web advancing means, web shearing means mounted for shifting movements transversely of the web direction of movement as it advances, electrically actuatable operating means forshifting the shearing means in accordance with lateral shifting of the web and means for controlling the operating means, comprising a' other of which is biased toward open position, n

said biasing being in the direction of an edge of the web, said switch unit also including a movable follower member normally urged into engagement with said web edge by the iirst one of said switch elements and holding said rst one of the switch elements open on a predetermined position of the web edge relative to said shearing means, said follower member being movable with said web edge upon shifting of said web away from said unit to permit said rst switch element t0 close and being movable under the influence of said web edge when the web shifts in the opposite direction to effect closing of the second switch element, the pair of biased switch elements beingarranged in parallel spaced relation to each other and adjacent one edge of the traveling web, the movable follower member of said switch unit comprising an elongated blade interposed between the pair of biased switch elements and the edge of the traveling web and having one face extending a. substantial distance along and normally in contact with said edge.

5. For use in a mechanism for accurately operating upon a traveling web of material to effect an operation on the web in predetermined relation to a particular line lengthwise of the traveling web wherein the mechanism includes web advancing means, means for performing said operation on said web mounted for shifting movements transversely of the direction of advance of the web, electrically actuatable means for shifting said operating means in either direction transversely of the direction of web advance and means for controlling the operating means to effect shifting of said web operating means upon lateral creeping of the web in either direction from a predetermined relation of said web operating means and web lines, an electric circuit for actuating said operating means and a switch unit in said circuit adapted to be disposed adjacent to said traveling web and in relatively xed relation to said web operating means; said switch unit including rst and second parallel switch elements one of which is biased toward the closed and the other of which is biased toward the open position relative to the position of one edge of said web, the iirst element when closed effecting actuation of the operating means to shift the web operating means in a direction away from said one web edge toward the opposite edge of said web, the second element when closed eiecting actuation of the operating means to shift the web operating means in the opposite direction, said control means also including a movable blade shaped Vmember extending between said one web edge and said switch elements and responsive to movements of said one web edge to hold the iirst element open while the second element is also open when the web operating means are in said predetermined relation and to permit the rst element to close upon movement of said one web edge in the direction of the other edge thereof and to close the second element upon movement of said web edge in the opposite drection.`

6. `For use in a slitting machine for acting on a traveling web subject to lateral creeping wherein there are a pair of cooperable slitting rolls arranged for shifting transversely of the web, electrically actuatable means for shifting the rolls in either direction and meansfor controlling the operating means to effect shifting of the rolls in the same direction and degree as creeping of the web, said control means comprising an electrical switch unit mounted adjacent an edge of the web for shifting in iixed relation to the rolls and includnga pivoted followermember adapted lto bear` on the adjacent web'edge, `a motor circuit including said switch unit; said switch unit including rst and second switch elements biased respectively toward closed and open position in the direction of the pivoted follower member and engageable thereby, the pivoted member in normal lateral position of the web edge relative to the switch unit being held by said edge in engagement with the rst switch element to hold it open While leaving the second switch element also open, and upon creeping of the Web in one direction or the other causing one or the other of the switch elements to close for effecting shifting of the rolls and switch unit in the direction of web creepage until the web edge again assumes said normal lateral position relative to the switch unit, the pair of biased switch elements being arranged in parallel spaced relation to each other and adjacent one edge of the traveling web and the pivoted member of said shiftable means comprising an elongated blade interposed between the pair of biased switch elements and the edge of the traveling web and having one face extending a substantial distance along and normally in contact with said edge.

7. For use in a machine for performing operations on a relatively continuous traveling web of material wherein the operations are to be performed in a predetermined relation to an edge of such material, such machine including an operation performing mechanism adjustable in each of opposite directions transversely of the web of the material, means including a reversible electric motor for adjusting said mechanism in said directions to maintain said mechanism in such transverse position as to perform its operations on said web in said predetermined relation to said edge and a blade-shaped web edge follower member pivotally mounted on an axis extending transverse to the plane of the web of material and adjacent to the path of movement of said material web edge, said follower blade having its side faces disposed transversely of the plane of the material web and having one side face extending a substantial distance along and normally in contact with said edge throughout a substantial part of such distance, a motor control circuit for operating said motor in either direction; a switch unit in said circuit operable by movements of said follower blade for controlling said circuit, including rst and second switch elements respectively biased toward closed and open position in the direction of said web edge, the first said element normally contacting the other side face of said blade and urging said blade constantly against said web edge, the pair of biased switch elements being arranged in parallel spaced relation to each other and adjacent one edge of the traveling web, and the web edge follower member being interposed between the pair of biased switch elements and the edge of the traveling web.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,133,297 Lewis Mar. 30, 1915 1,333,588 Lewis Mar. 9, 1920 1,458,396 Putt Sept. 18, 1923 1,740,535 Bramming Dec. 24, 1929 1,388,436 Richards Nov. 22, 1932 2,237,341 Dungler Apr. 8, 1941 2,410,249 Spencer Oct. 29, 1946 

